Burglar-alarm wall construction



Aug. 22, 1939. R. s. KAHN BURGLAR-ALARM WALL CONSTRUCTION Filed Feb. 11, 1957 l| Il I I| I I I I I I W nu ' INVENTOR. A? .5? KA/v A/ A TTORNE Y.

Patented Aug. 22, 1939 UNITED STATES PATENT oFFicE BURGLAR-ALARM WALL CONSTRUCTION Robert S. Kahn, Brooklyn, N. Y.

Application February 11, 1937, Serial No. 125,217

One object of this invention is the provision of wall sections, such as are commonly used in covering the skeletal frame of the walls and partitions of houses and other buildings, with means is mounted integrally in the sections so that the completed wall will serve, in combination with an electrical circuit, as the means for setting off a burglar alarm if a hole is dug through the wall for the entry of a persons body therethrough.

The invention is illustrated and described below to set forth one way in which the above object may be attained, but it may also be attained in oher ways, as will be observed below.

The above and other objects will become apparent in the description below, in which characters of reference refer to like-named parts in the accompanying drawing.

Referring briefly to the drawing, Figure 1 is a diagrammatic view illustrating a portion of a wall formed of sections constructed in accordance with this invention, together with a wiring diagram.

Figure 2 is a fragmentary perspective view,

partly in section, of a wall section.

Figure 3 is a. perspective view of the switch for setting the alarm circuit.

Referring in detail to: the drawing, the nu.- meral I0 indicates a Wall board or section formed of any material of which such sections are commonly made. On each end of the section. I0, a metal strip I I is imbedded witha peripheral projection I2 of the section I0 surrounding the strip II. A wire I3 of small diameter and light Weight, such as might be readily severed if a small amount of pressure is applied thereto, is set integrally and concealed within, the section I0, and possesses a series of spaced-apart parallel loops I4. The distance between the loops I4 is not over approximately five or six inches, so that this distance would be insufilcient to permit a persons body to pass between adjacent loops. One end I5 of the wire I3 is attached in any desirable manner to the strip II on one end of the section I0, and the other end I6 of the wire I3 is similarly secured to the strip II at the opposite end of the section I0. In covering the wall skeleton with the sections I0, the latter are set end to end with the strips II of each section contacting with the strips II of adjacent sections. A lead wire I1 is secured in any desirable manner to the strip I I which lies at the end of a series of such sections I0, and a similar wire I8 is attached to the strip I I at the opposite end of such a series. The wire I1 leads through a relay I9 to a battery or other source of electric supply 20. From the battery 20, a wire 2I joins a wire 22 which leads to one pole 23 of a switch 24. The directly opposite pole 25 of the switch 24 has the lead I8 secured thereto. The wire 5 22 is continued beyond the lead 2| to the armature 26 of the relay I9. The relay contact 21 leads through a wire 28 to an alarm 29, and the wire 30 connects the other side of the alarm 23 with the pole 3| of the switch 24. Finally, a 10 wire 32 joins the pole 33 of the switch 24 with the battery 20 on the same side as the wire I1.

The switch 24 comprises a yoke having its blades or arms 34 and 35 separated by an insulated block 36, and a pivoted handle 31 rigid 15 with the yoke.

As shown in the wiring diagram of Figure 1, the circuit through the wire l1, the strips II, the looped wires I3, and the wire I8 is open, that is, the alarm circuit is open. In setting 0 the alarm circuit so that it will be actuated in the event that any portion of any of the wires I3 is severed, the switch 24 is closed. When the latter is done, it is desirable that the circuit through the relay I9 is closed first so as to pre- 25 vent sounding of the alarm at that instant. This is accomplished by having the poles 23 and 25 raised higher above the base 38 than the poles 3I and 33, so that the arm 34 of the switch 24 will bridge the poles 23 and 25 before the arm 30 35 bridges the poles 3I and 33. At the instant of contact of the arm 34 with the poles 23 and 25, current flows from the battery 20 through lead I1, relay I9, to the topmost strip II, down through the series of Wires I3, out at the bottom 35 strip II, through lead I8, pole 25, arm 34, pole 23, lead 22, and lead 2|. Thus, the energized relay I9 attracts the armature 26 and separates the latter from its contact 21. As the arm 35 of the switch 24 descends into contact with its poles 40 3I and 33, the circuit through the alarm 29 and battery 20 is closed at every point excepting at that between the armature 26 and contact 21.

If now the wall in which the sections I0 are mounted is broken through by chiseling or in 45 any other manner so that any of the wires I3 are severed at any point, the circuit through the relay I9 is instantly opened so that the armature 26 is released and swings back to contact with the contact 21, and thus closes the battery circuit 5 through the alarm, causing the latter to sound. If a series of vertical sections ID are provided side by side to cover an entire wall, a single alarm circuit such as that shown in Figure 1 may be used with a plurality of relay circuits 55 with each of the latter connected in one vertical series of sections l0.

As set forth above, the construction embodies the sounding of an alarm upon the severance of one of the wires [3. A modified construction might be used, however, in which it will not be necessary to actually sever a wire in the wall section, but simply to cause opposite sides of any loop I4 to be brought into mutual contact. In such case, the relay would be of such design that upon the reduction of the total resistance of the series of wires I3 between the strips at the top and bottom of such a vertical series of sections In, the relay will receive sufiicient additional current to attract its armature and thus close an alarm. circuit. However, it is believed that the construction illustrated and described is the most practical, as by the provision of relatively soft thin and easily broken wires l3, it will be impossible for any person to chisel a hole through a wall without severing such a wire.

By the term wall used in the above description, is implied also ceiling and floor, as similar sections ll] may be applied to ceilingsand. floors in the same manner and for the same purpose.

A wall having sections such as those above described mounted therein, could be used as a radio aerial by connecting one end of the wire [3 of any section with the antenna post of a radio.

Obviously, modifications in. form and structure may be made without departing from the spirit and scope of the invention.

I claim:

A burglar alarm wall construction consisting of the provision of a plurality of wall sections adapted to be mounted end to end to cover a length of wall, each of said sections comprising a substantially rectangular body formed of any desired building material, metallic strips imbedded in opposite edges of each section, a looped wire imbedded in said body and having its ends secured to the said strips at the opposite edges of said body, the loops of said wire being relatively close together, said wire being formed of a relatively fragile material.

ROBERT S. KAHN. 

